Pixel-differentiated CCD architecture

ABSTRACT

A pixel-differentiated CCD imager architecture may include: a plurality of photo-sensing pixels arranged in a matrix, each pixel being classified according to type from among a plurality of photo-sensing pixel types; and read circuitry controllable to respectively read one or more of a second type of pixel independently of reading a first type of pixel, the reading of one or more first type pixels representing a sampling of fewer than all of the plurality of pixels, the sampling being obtainable without having to read all of the plurality of pixels. A related method and digital camera may include features similar to elements of the pixel-differentiated CCD imager architecture.

BACKGROUND OF THE INVENTION

An image sensor is a fundamental component that measures or captures aspatial, frequency and/or intensity distribution of the light to whichit is exposed. An example of a system using such a sensor is a digitalcamera system (irrespective of whether the system captures still ormoving images).

The image sensor generally does the following. Impinging light isconverted to stored charge (electrons) that are transferred off thepixel area of the image sensor and then converted into voltages (analogsignals). The analog signals are then converted into digital values thatrepresent an image to which the image-sensor was exposed.

The charge-coupled device (CCD) remains the most popular technology forimplementing an image sensor. A competing technology is the CMOS imagesensor. An advantage of a CMOS sensor over the CCD sensor is that pixelson a CMOS sensor are individually addressable such that one or a few ofthe pixels can be read without having to read all of the pixels. Incontrast, CCD imagers according to the Background Art have no provisionfor individually addressing one or more, but fewer than all, pixels.

SUMMARY OF THE INVENTION

One of the embodiments of the invention is directed to apixel-differentiated CCD imager architecture. Such an architecture mayinclude: a plurality of photo-sensing pixels arranged in a matrix, eachpixel being classified according to type from among a plurality ofphoto-sensing pixel types; and read circuitry controllable torespectively read one or more of a second type of pixel independently ofreading a first type of pixel, the reading of one or more first typepixels representing a sampling of fewer than all of the plurality ofpixels, the sampling being obtainable without having to read all of theplurality of pixels.

Another one of the embodiments of the invention is directed to method ofoperating a CCD imager, the imager having a pixel-differentiatedarchitecture that includes a first plurality of photo-sensing pixelsarranged in a matrix, each pixel being classified according to type fromamong a plurality of photo-sensing pixel-types including a first typeand a second type of photo-sensing pixel. Such a method may include:reading one or more of the second type pixels independently of readingthe first type pixels, the reading of one or more second type pixelsrepresenting a sampling of fewer than all of the plurality of pixels,the sampling being obtainable without having to read all of theplurality of pixels.

Another one of the embodiments of the invention is directed to anotherpixel-differentiated CCD architecture. Such an architecture may include:a first plurality of non-sampling arrays that include a first type ofphotosensor; and a second plurality of sampling arrays that include thefirst type of photosensor and a second type of photosensor, eachsampling array being arranged so that sample-information from the secondtype photosensor can be transferred out of the sampling array withoutthe sample-information having to be conveyed via any of the first typephotosensors in the sampling array; and transfer means for transferringinformation out of one or more selected second type photosensors withoutalso having to transfer information contained in first typephotosensors.

Still another of the embodiments of the invention is directed to anotherpixel-differentiated imager architecture. Such an architecture mayinclude: a first plurality of blocks, each block having a secondplurality of photo-sensing pixels arranged in a matrix, each pixel beingclassified according to type from among a plurality of types including afirst type and a second type of photo-sensing pixel; and read circuitrycontrollable to respectively read one or more of the second type pixelsindependently of reading the first type pixels, the read-circuitry notbeing controllable to read all of the pixels individually. Another oneof the embodiments of the invention is directed to a digital camera.Such a camera may include: a pixel-differentiated CCD imagerarchitecture including a plurality of photo-sensing pixels arranged in amatrix, each pixel being classified according to type from among aplurality of photo-sensing pixel-types including a first type and asecond type of photo-sensing pixel, and read circuitry controllable torespectively read one or more of the second type pixels independently ofreading the first type pixels, the reading of one or more second typepixels representing a sampling of fewer than all of the plurality ofpixels, the sampling being obtainable without having to read all of theplurality of pixels; and image processing means for controlling the readcircuitry and processing the output of the pixel-differentiated CCDimager into a digital representation of an image captured by thepixel-differentiated CCD imager.

Another one of the embodiments of the invention is directed to anotherdigital camera. Such a camera may include: a pixel-differentiated CCDimager including a first plurality of blocks, each block having a secondplurality of photo-sensing pixels arranged in a matrix, each pixel beingclassified according to type from among a plurality of photo-sensingpixel-types including a first type and a second type of photo-sensingpixel; and read circuitry controllable to respectively read one or moreof the second type pixels independently of reading the first typepixels, the read-circuitry not being controllable to read all of thepixels individually; and image processing means for controlling the readcircuitry and processing the output of the pixel-differentiated CCDimager into a digital representation of an image captured by thepixel-differentiated CCD imager.

Additional features and advantages of the invention will be more fullyapparent from the following detailed description of example embodimentsand the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are: intended to depict example embodiments of theinvention and should not be interpreted to limit the scope thereof.

FIG. 1 is a block diagram of a digital camera architecture according toan embodiment of the invention.

FIG. 2 is a block diagram of a portion of a pixel-differentiated CCDimager according to an embodiment of the invention.

FIGS. 3A-3D and 4A-4D are more detailed depictions of a sampling arrayon the CCD imager of FIG. 2 and how the array operates in a samplingmode, according to an embodiment of the invention.

FIG. 5 is a block diagram of sampling:non-sampling array ratiodistributions according to an embodiment of the invention.

FIG. 6A-6B are block diagrams of a portion of anotherpixel-differentiated CCD imager according to an embodiment of theinvention.

And FIG. 7 is an alternative to FIGS. 6A-6B, FIG. 7 being a moredetailed depiction of an alternative sampling array on the CCD imager ofFIGS. 6A-6B and how the array operates, according to an embodiment ofthe invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

An embodiment of the invention, at least in part, includes therecognition of the following. Selectively sampling and/or reading areasof an image sensor, e.g., for differentially shuttering areas of theimager, adaptively setting exposure time, performing rapid sequentialreads of dynamic portions of an image without corresponding reads ofstatic image areas (thereby reducing processing load), etc., would bedesirable, especially if it also not necessary to read all areas of theimage sensor. The individually-addressable pixels in a CMOS image sensoraccording to the Background Art would be well suited to selectivesampling/reading. But not every pixel needs to be individuallyaddressable for selective sampling/reading to be effective. Instead, itis sufficient to designate a subset of individually addressable pixels(selected pixel readability) and associate with each of these pixels ablock of pixels that may be independently read within the array ofpixels (block readability). The sampling (a.k.a.individually-addressable) pixels can be treated as representative oftheir associated blocks. While an imager in which all pixels areindividually addressable is not practical with a CCD implementation,there can be practical implementations of CCD imagers having blockreadability and selected pixel readability. Alternatively, a CMOS imagerhaving block readability and selected pixel readability (but not all ofthe pixels being individually addressable) would be easier/less costlyto implement than a CMOS imager in which every pixel is individuallyaddressable.

FIG. 1 is a schematic block diagram of hardware architecture of adigital camera 100 according to an embodiment of the invention. Thedigital camera 100 of FIG. 1 includes an imager 102 having blockreadability and selected pixel readability (but not all of the pixelsbeing individually addressable), according to an embodiment of theinvention (to be discussed below). The imager 102 alternatively can bedescribed as a pixel-differentiated imager.

The imager 102 can be a charge-coupled-device (CCD), or a CMOS device,each of which can output an analog signal.

The analog signal from the imager 102 can be provided to ananalog-to-digital (A/D) device 104. Optionally, the A/D device 104 canbe provided on the same integrated circuit as the imager 102. The A/Dconverter 104 provides a digitized version of the output of the imager102 to an application-specific integrated circuit (ASIC) 106. The ASIC106 provides clock signals to clock drivers 108 that are used to operatethe imager 102.

The camera 100 also includes: zoom (optional), focus, iris and shuttermechanisms 110 that are operated via motor drivers 112 by the ASIC 106;and a flash unit 114 operated via a strobe drive 116 controlled by theASIC 106. For memory devices, the digital camera 100 includes: avolatile memory 118, e.g., a synchronous dynamic random access memory(SDRAM) device; and a non-volatile memory 120, e.g., an internal flashmemory device. Also, a connector 122 for connection to an externalcompact flash memory device is provided. The ASIC 106 can also connectto an external work station 124, e.g., through a universal serial bus(USB) connector 126. The digital camera 100 also includes amicrocontroller 128 with which the ASIC 106 can communicate.

Other architectures for the camera 100 are contemplated. Each sucharchitecture can include one or more processors, one or more volatilememory devices and one or more non-volatile memory devices.

FIG. 2 is a block diagram of a portion of a pixel-differentiated CCDimager 200 according to an embodiment of the invention. Only a portionof the pixel-differentiated imager 200 is shown in order to simplify thedepiction. There are further simplifications in FIG. 2, as will bediscussed below.

The imager 200 includes a first plurality of photo-sensing pixels, themajority of which can be classified as a first type of photo-sensingpixel 202 (hereafter also referred to as a Type I pixel). The firstplurality further includes pixels that can be classified as a secondtype of photo-sensing pixel 204 (hereafter also referred to as Type IIpixel). The Type I pixels 202 can be thought of as non-sampling pixels.In contrast, the Type II pixels can be thought of as sampling pixels.Physically, the Type I pixels 202 and the Type pixels 204 are the samebut for the addressing and control lines going the them, respectively,which give rise to their different classifications. More about thedifferences between Type I (non-sampling) and Type II (sampling) pixelswill be discussed below. Alternatively, additional types of pixels canbe provided on the image sensor 200.

The first plurality of photo-sensing pixels is organized into banks 206₁, 206 ₂ and 206 ₃. Each bank 206 _(i) can be described as having rows212 and columns 214. Each bank 206 _(i) has a linear array 208 _(i) (208₁, 208 ₂ and 208 ₃, respectively) of information-transferring cells 210adjacent one of its sides, e.g., here its lower side. In the CCDimplementation, the array 208 _(i) can be a horizontal linear CCD(HCCD); for simplicity, the array 208 _(i) will be referred to as theHCCD 208 _(i).

Charge that is produced in each of the pixels 202 and 204 is, e.g., inthe CCD implementation, transferred by bucket-brigading vertically downeach respective column 214 to the corresponding HCCD 208 _(i) and movingtransversely (e.g., here horizontally to the right) through HCCD 208_(i) to a corresponding known charge amplifier 220 _(i) (220 ₁, 220 ₂and 220 ₃, respectively).

Each bank 204 _(i) is organized into arrays, each array being either asampling array 216 or a non-sampling array 218. A sampling array 216includes a Type II pixel 204 at the bottom, closest to the correspondingHCCD 208 i. The other pixels in the array 216 are Type I pixels 202. Thenon-sampling array 218 includes Type I pixels 202 but does not includeany Type II pixels 204.

An imager 200 can be formed entirely of sampling arrays 216 (i.e.,without non-sampling arrays 218) or by a combination of sampling arrays216 and non-sampling arrays 218. Where both are present, any number ofratios of sampling:non-sampling arrays can be used depending upon thecircumstances for which the imager 202 is contemplated for use. Theratio of sampling:non-sampling arrays can be constant throughout theimager 200, or it can be non-uniform. For example, as depicted in FIG.5, each of a central portion 502 and a peripheral region 504 of animager 500 can have constant sampling:non-sampling ratios, with theratio in the central region 502 being higher (relatively more samplingarrays 216) than in the peripheral region 504. As another alternative,the ratio of sampling:non-sampling arrays can be a gradient thatdecreases radially (i.e., the density of sampling arrays 216 decreases)from about the center of the imager 500 toward the periphery 506, asindicated by the arrow 508 depicted in phantom lines.

Returning to FIG. 2, it depicts the banks 206 ₁, 206 ₂ and 206 ₃ in theimager 200 as each being of a different constant ratio ofsampling:non-sampling arrays. This can be an example of the decreasinggradient of sampling-array-218 density. One of ordinary skill would alsounderstand that every bank 206 _(i) in the imager 200 can have thesampling:non-sampling ratio of the bank 206 ₁ (namely, only samplingarrays 216 and no non-sampling arrays 218), or the bank 206 ₂ (namely,three 1 sampling array 216 for every 3 non-sampling arrays 218, i.e.,25% sampling arrays 216) or the bank 206 ₃ (namely, three 1 samplingarray 216 for every 7 non-sampling arrays 218, i.e., 12.5% samplingarrays 216) or some other ratio, e.g., a ratio in which there is asignificantly greater number of Type I pixels 202 in a sampling array216 relative to the single Type II pixel 204. Such a lower density typeof imager 200 would be more difficult to depict in a drawing and so hasnot been depicted here. Again, the ratio of sampling:non-sampling arraysis not a limitation upon the invention.

Similarly, for simplicity, FIG. 2 depicts each of the sampling array 216and the non-sampling array 218 as having a total of 8 pixels. This is aconvenient number that permits three banks 208 _(i) to be depicted in adrawing, but any number of pixels can be selected for inclusion in anarray 216/218. As before, the number of pixels in an array will dependupon the circumstances for which the imager 202 is contemplated for use.The number of pixels in an array 216/218 is not a limitation upon theinvention.

Lastly, the overall size of the imager 200 has similarly been simplifiedin FIG. 2. In practice, an imager 200 will have a great many more pixelscomprising the first plurality, but that would make for a much morecomplicated drawing. In other words, the total number of photo-sensingpixels 202/204 in the imager 200 of FIG. 2 will depend upon thecircumstances for which the imager 202 is contemplated for use.

FIG. 3A-3D are more detailed depictions of a sampling array 300 thatcorresponds to the sampling array 216 on the imager 200 of FIG. 2, aswell as how the sampling array 300 operates in a sampling mode,according to an embodiment of the invention. In FIG. 3A, a Type II pixel302 corresponds to the Type II pixel 204, Type I pixels 304-316correspond to the Type I pixel 202, column 318 corresponds to the column214, HCCD 320 corresponds to the HCCD 208 _(i) and theinformation-transferring cells 322-328 correspond to theinformation-transferring cells 210.

In the sampling mode, the array 300 is controllable so that only theinformation in the Type II pixel 202 is sampled/read. The information inthe Type I pixels 304-316 is not read in the sampling mode. Dependingupon value of the sample read from the Type II pixel 302, the array 300is controllable in a read-mode (more detail to be discussed below interms of FIGS. 4A-4D) so that the information in the Type I pixels304-316 is read. The term “controllable” is used here to connote thatthe imager 200, particularly the array 300, is configured with clockinglines and address/control lines so that the clocking circuit 108 andcontrol logic, e.g., in the ASIC 106, respectively, can control thearray 300 to behave according to the sampling-mode or the read-mode.

As shown by the exploded view 330 in FIG. 3A, the Type I pixels 304-316(and also the Type II pixel 302) can be formed by a known configurationof a linear array of photo-sensing cells/stages 332, a linear array oftransfer gates 334 and a linear array of transport cells/stages 336. Asshown by the exploded view 330 in FIG. 3A, the HCCD 320 can be formed bya known configuration of a linear array of transfer gates 340 and alinear array of transport cells/stages 342.

In the sampling mode, the information in the Type II pixel 302 issampled (as indicated by the legend “smpl” in the Type II pixel 302) andthen (e.g., in the CCD implementation) bucket-brigaded to thecorresponding charge-transferring cell 324 in the HCCD 320, as indicatedby the arrow 342 depicted in phantom lines. No horizontalbucket-brigading in the HCCD 320 yet takes place. Before the transfer, adon't-care condition applies to the information in thecharge-transferring cells 322-328, as indicated by the “null” legend inthe cells 322 and 324. Again, the information in the Type I pixel 304 isnot correspondingly bucket-brigaded into the Type II pixel 302 duringthe sampling mode.

In FIG. 3B, the sampled information previously in the Type II pixel 302is shown in the charge-transferring cell 324. Because the information inthe Type I pixel 304 does not get shifted into the Type II pixel 302 inthe sampling-mode, a null is indicated in FIG. 3B for the Type II pixel302. As no horizontal shifting in the HCCD 320 has yet occurred, a nullremains indicated in the cell 322. Next, the HCCD is shifted one stageto the right as indicated by the arrows 344.

In FIG. 3C, the sampled information previously in the cell 324 is shownin the cell 324, and the null previously in the cell 322 is shown in thecell 324. As the information in the Type I pixels is not being read(shifted downwardly to the cell 322) in the sampling-mode, a nullremains indicated for the Type II pixel 302. In FIG. 3D, the sampledinformation previously in the cell 326 is shown in the cell 328, thenull previously in the cell 324 is shown in the cell 326 and a nullremains indicated for the Type II pixel 302.

One of ordinary skill would appreciate that the shifting of the HCCD inFIGS. 3B-3D would continue until information from all of the sampledType II pixels 302/204 serviced by the HCCD 320/208 _(i) is moved to thecorresponding charge amplifier 220 _(i) and converted to a voltage.

FIG. 4A-4D depict the sampling array 300 and how the array operates in anon-sampling mode, according to an embodiment of the invention. In thenon-sampling mode, the information in the Type I pixels 304-316 is read.The decision to enter sampling mode can be based upon an evaluation ofthe sampled-information obtained from the Type II pixel 302 in thesampling mode. Details of how to determine when to enter the read-modebased upon the results of the sampling-mode can be found in a copendingrelated application by the same inventors (Attorney Docket No.10018579-1 <HDP#6215-000066>, filed the same day as the presentapplication and entitled “Adaptively Reading One Or More But Fewer ThanAll Pixels Of Image Sensor”), the entirety of which is herebyincorporated by reference.

In FIG. 4A, it is assumed that the sampling mode has taken place suchthat a null is present in the Type II pixel 302 (see the discussion ofFIGS. 3A-3B above). The information accumulated in the Type I pixels304-316 is (e.g., in the CCD implementation) bucket-brigaded to thecorresponding charge-transferring cell 324 in the HCCD 320. In moredetail, the information in the Type I pixels 304-316 is shifted 2 pixelsdownward resulting in FIG. 4C. FIG. 4B is intermediate to FIGS. 4A and4C and represents the information in the Type I cells 304-316 havingbeen shifted downward only by one pixel such that the null previously inthe Type II pixel 302 is in the corresponding charge-transferring cell322.

In FIG. 4C, the data previously in the Type I pixel 304 is in thecharge-transferring cell 322. One of ordinary skill would appreciatethat the HCCD 320/208 _(i) is horizontally shifted until the informationfrom all of the Type I pixels 304 is moved out of the HCCD 320/208 _(i)to the corresponding charge amplifier 220 _(i) and converted to avoltage.

In FIG. 4B, a null is depicted at top of the sampling array 300 in theType I pixel 316 to reflect the downward shift by one pixel. In FIG. 4C,a null is depicted in the Type I pixels 316 and 314 to reflect thedownward shift by two pixels; similarly, a null is also depicted in theType I pixel 312 at FIG. 4D to reflect the downward shift by threepixels. And, at FIG. 4D, the data from the Type I pixels 304 and 306 isin the charge-transferring cells 324 and 326, respectively.

Information obtained in the read-mode is missing a componentcorresponding to the Type II pixel 302 because it was previously read inthe sampling-mode. In, e.g., the ASIC 106, the missing information canbe interpolated from the neighboring information.

The non-sampling array 218 can be read in the read-mode comparably tohow the sampling array 216 is read, as described in FIGS. 4A-4D. As thenon-sensing array 218 does not have a Type II pixel 302, there is nomissing component that needs to be interpolated.

FIG. 6A is a block diagram of a portion of another pixel-differentiatedCCD imager 600 according to an embodiment of the invention. In somerespects, the imager 600 is the same as the imager 200 and will adoptthe same reference numbers for which little (or no) further explanationis given. In other respects, the imager 600 has features similar to theimager 200, the similar features being given similar reference numbersand additional explanation. Also, similar simplifications apply to FIG.6A (and FIGS. 6B and 7) as for FIG. 2.

Instead of the combination of the linear sampling arrays 216 and thelinear non-sampling arrays 218, the imager 600 is shown as having onlythe sampling arrays 616 in the banks 208 _(i). Each of the arrays 616includes Type I pixels 602 and a Type II pixel 604. For ease ofrecognition, a heavy line has been depicted around the Type I pixels 602for every other array 616.

Despite having an appearance (upon first impression) of more than onecolumn (i.e., which would otherwise connote a two-dimensional array),the sampling array 616 is a linear array of photo-sensing pixels602/604, albeit a linear array arranged into a space-fillingconfiguration. In FIG. 6, the space-filling configuration is apiecewise-continuous spiral. FIG. 6B is a more detailed depiction of thepiecewise-continuous spiral arrangement of the sampling array 616 ofFIG. 6A and how the array 616 operates, according to an embodiment ofthe invention.

In FIG. 6B, the end of the linear array corresponds to the Type I pixel652, which is analogous to the top Type I pixel 316 in the sensingimager 316 and represents the Nth photo-sensing pixel (here, the 63^(rd)pixel, where the Type II pixel 302 is the zeroith pixel). The type Ipixel 650 represents the N-1 pixel, etc. Charge is bucket-brigaded in aspiral direction counterclockwise moving away from the Type I pixel 652.Similar to the imager 200, in the exploded view 630, the Type I pixels604, 608, 648 ₁, 648 ₂, 648 ₃, 650 and 652 (and also the Type II pixel602) can be formed by a known configuration of a linear array ofphoto-sensing cells/stages 632, a linear array of transfer gates 634 anda linear array of transport cells/stages 636.

In the spiral arrangement of FIGS. 6A-6B, the footprint of thephoto-sensing elements of the array 332, the transfer gates 334 and thetransport stages 336 can be in a shape other than the typical rectangleor square. Such a shape, e.g., a hexagon, would be better suited to tilea two-dimensional area.

FIG. 7 is an alternative to FIGS. 6A-6B, FIG. 7 being a more detaileddepiction of an alternative sampling array on the CCD imager of FIGS.6A-6B and how the array operates, according to an embodiment of theinvention. Instead of the piecewise-continuous spiral arrangement of thesensing array 616, the sensing array 716 is a linear array arranged intoa space-filling configuration taking the form of a raster. In FIG. 6, bycontrast, the space-filling configuration is a piecewise-continuousspiral. Otherwise, FIG. 7 has corresponding item numbers 704, 706, 708,750 and 752.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications are intended to be included within the scope of thepresent invention.

1. A pixel-differentiated CCD imager architecture comprising: aplurality of photo-sensing pixels arranged in a matrix, each pixel beingclassified according to type from among a plurality of photo-sensingpixel types; and read circuitry controllable to respectively read one ormore of a second type of pixel independently of reading a first type ofpixel, the reading of one or more first type pixels representing asampling of fewer than all of the plurality of pixels, the samplingbeing obtainable without having to read all of the plurality of pixels.2. The CCD imager architecture of claim 1, wherein operation of the readcircuitry includes bucket brigading of charge.
 3. The CCD imagerarchitecture of claim 1, wherein: there are fewer second type pixelsthan first type pixels.
 4. The CCD imager architecture of claim 3,wherein: the second type pixels are arranged amongst the first typepixels such that the second type pixels are uniformly distributedamongst the first type pixels.
 5. The CCD imager architecture of claim1, wherein: a total area covered by the plurality of pixels is organizedinto a central portion and peripheral portion; the second type pixelsare arranged amongst the first type pixels such that a density of secondtype pixels in the central portion is higher than in the peripheralportion.
 6. The CCD imager architecture of claim 5, wherein adistribution of the second type pixels amongst the first type pixels is,for each of the respective central and peripheral portions, one of auniform distribution or a gradient of density of second type pixelsdecreasing radially from a center of the total area covered by theplurality.
 7. The CCD imager architecture of claim 1, wherein: the firsttype pixels are organized into blocks; and the read circuitry is furthercontrollable to read selected ones of blocks.
 8. The CCD imagerarchitecture of claim 7, wherein the reading of the selected blocks offirst type pixels represents a sampling of fewer than all of blockswithout having to read all of the blocks.
 9. The CCD imager architectureof claim 1, wherein: the plurality is a first plurality; rows of thematrix are grouped into a second plurality of banks, each bank beingorganized into a third plurality of arrays of the pixels; the pixelarrays are arranged to transfer information along a first direction; andthe CCD imager architecture further comprises a fourth plurality ofinformation-transfer linear arrays of information-transferring cells,each information-transfer array being associated with at least one bankand arranged adjacent to a side of the at least one bank such that twoneighboring banks are separated by an information-transferringlinear-array.
 10. The CCD imager of claim 9, wherein: each pixel arrayincludes pixels of a first type; a predetermined number of the pixelarrays are sampling arrays that further include a second type of pixel;each sampling array is arranged so that sample-information from thesecond type pixel can be transferred to the associatedinformation-transfer array without the sample-information having to beconveyed via any of the first type pixels in the sampling array; thesampling array being controllable to read the second type pixel withouthaving to read all of the first type pixels in the sampling array. 11.The CCD imager of claim 10, wherein each pixel array is configured as alinear array of pixels that is controllable to transfer information in asecond direction perpendicular to the first direction.
 12. The CCDimager of claim 11, wherein each linear array is arranged into aspace-filling configuration that covers an area that would otherwisecorrespond to a two-dimensional array.
 13. The CCD imager of claim 12,wherein the space-filling configuration is one of a raster and apiece-wise continuous spiral.
 14. A method of operating a CCD imager,the imager having a pixel-differentiated architecture that includes aplurality of photo-sensing pixels arranged in a matrix, each pixel beingclassified according to type from among a plurality of photo-sensingpixel-types including a first type and a second type of photo-sensingpixel, the method comprising: reading one or more of the second typepixels independently of reading the first type pixels, the reading ofone or more second type pixels representing a sampling of fewer than allof the plurality of pixels, the sampling being obtainable without havingto read all of the plurality of pixels.
 15. The method of claim 14,further comprising bucket-brigading of charge.
 16. The method of claim14, further comprising: organizing the first type pixels into blocks;and selectively transferring information from selected ones of theblocks.
 17. The method of claim 16, further comprising: selectivelytransferring fewer than all blocks without having to transferinformation from all of the blocks.
 18. The method of claim 14, wherein:the plurality is a first plurality; rows of the matrix are grouped intoa second plurality of banks, each bank being organized into a thirdplurality of arrays of the pixels; and the pixel-differentiatedarchitecture further includes a fourth plurality of information-transferlinear arrays of information-transferring cells, eachinformation-transfer array being associated with at least one bank andarranged adjacent to a side of the at least one bank such that twoneighboring banks are separated by an information-transferringlinear-array, each pixel array includes first type pixels, and apredetermined number of the pixel arrays are sampling arrays thatfurther include a second type pixel; and the method further comprisestransferring sample-information from the second type pixel to theassociated information-transfer array without having to convey thesample-information via any of the first type pixels in the samplingarray.
 19. The method of claim 18, further comprising: reading thesecond type pixel of a sampling array without having to read all of thefirst type pixels in the sampling array.
 20. A pixel-differentiated CCDarchitecture comprising: a first plurality of non-sampling arrays thatinclude a first type of photosensor; and a second plurality of samplingarrays that include the first type of photosensor and a second type ofphotosensor, each sampling array being arranged so thatsample-information from the second type photosensor can be transferredout of the sampling array without the sample-information having to beconveyed via any of the first type photosensors in the sampling array;and transfer means for transferring information out of one or moreselected second type photosensors without also having to transferinformation contained in first type photosensors.
 21. Apixel-differentiated imager architecture comprising: a first pluralityof blocks, each block having a second plurality of photo-sensing pixelsarranged in a matrix, each pixel being classified according to type fromamong a plurality of types including a first type and a second type ofphoto-sensing pixel; and read circuitry controllable to respectivelyread one or more of the second type pixels independently of reading thefirst type pixels, the read-circuitry not being controllable to read allof the pixels individually.
 22. The pixel-differentiated imagerarchitecture of claim 21, wherein the imager is implemented as a CCD.23. The pixel-differentiated imager architecture of claim 21, whereinthe read circuitry is controllable to read respectively read one or moreof the blocks without having to read all of the blocks, theread-circuitry not being controllable to read all of the first typepixels in a block individually.
 24. A digital camera comprising: apixel-differentiated CCD imager architecture including a plurality ofphoto-sensing pixels arranged in a matrix, each pixel being classifiedaccording to type from among a plurality of photo-sensing pixel-typesincluding a first type and a second type of photo-sensing pixel, andread circuitry controllable to respectively read one or more of thesecond type pixels independently of reading the first type pixels, thereading of one or more second type pixels representing a sampling offewer than all of the plurality of pixels, the sampling being obtainablewithout having to read all of the plurality of pixels; and imageprocessing means for controlling the read circuitry and processing theoutput of the pixel-differentiated CCD imager into a digitalrepresentation of an image captured by the pixel-differentiated CCDimager.
 25. A digital camera comprising: a pixel-differentiated CCDimager including a first plurality of blocks, each block having a secondplurality of photo-sensing pixels arranged in a matrix, each pixel beingclassified according to type from among a plurality of photo-sensingpixel-types including a first type and a second type of photo-sensingpixel; and read circuitry controllable to respectively read one or moreof the second type pixels independently of reading the first typepixels, the read-circuitry not being controllable to read all of thepixels individually; and image processing means for controlling the readcircuitry and processing the output of the pixel-differentiated CCDimager into a digital representation of an image captured by thepixel-differentiated CCD imager.